Embodiments of the present disclosure relate to an anti-fuse, an anti-fuse array and a method of operating the same and, more particularly, to an anti-fuse array having improved program efficiency.
An anti-fuse of a semiconductor device is initially in an insulated state and transforms to a conductive state when a voltage greater than its threshold voltage is applied. An anti-fuse includes a program transistor and a select transistor.
An anti-fuse array includes program transistors, select transistors, and bit lines. One program transistor, one select transistor, and one bit line are selected to program a target cell.
When a high voltage is applied to the program gate of the program transistor, the gate insulation film of the program gate ruptures due to the voltage difference between the high voltage program gate and the low voltage bit line. More specifically, a voltage sufficient for forming a conductive channel is applied to the select gate of the select transistor, transferring the program gate voltage. Then, the voltage difference between the program gate and the bit line acts on the gate insulation film. This results in the gate insulation film of the program gate rupturing, completing the program operation.
Anti-fuses allow for memory cell repairs to be performed at a package level, may increase the number of net dies, may improve product characteristics, and may overcome device and fabrication limitations that are present when using conventional laser fuses. Because of the above-mentioned characteristics of the anti-fuse, it is expected that anti-fuses will become more widely used in various technical fields.
For an anti-fuse to properly function, a high quality oxide film must be formed so that current does not leak unless the anti-fuse is programmed. In addition, after programming, it is important to ensure that the programming operation was a success (i.e. that the gate oxide film was properly ruptured).
As the number of necessary fuses increases and the size of each fuse increases, the chip area occupied by the anti-fuse also unavoidably increases. Therefore, it is always a goal to find ways to increase anti-fuse integration while maintaining performance characteristics.